Helmets function to provide protection while minimizing interference with the performance or enjoyment of an otherwise dangerous activity. The shape of a helmet may be adapted to provide both protection and comfort. For example, a helmet may be shaped to increase ventilation, or to reduce weight and volume. Some helmets are made up of two or more bodies of energy-absorbing material to form shapes that would be difficult, if not impossible, to achieve in a single molded piece. Conventional helmets are made by joining helmet bodies with adhesives, or by in-molding the helmet bodies together.